1. Field of the Invention
The present invention relates to control apparatus for electrically-powered vehicle.
Priority is claimed on Japanese Patent Application No. 2005-258928, filed Sep. 7, 2005, the content of which is incorporated herein by reference.
2. Description of Related Art
Conventional control devices that increase the gripping force of driving wheels by limiting the output of a driving motor (see, for example, Published Japanese Patent No. 3446559) are well known as devices for controlling the regenerative torque due to the regenerative operation of driving motor and for traction control for suppressing spinning of the driving wheel when an excessively large driving force acts on the road surface from the tires in hybrid vehicles that transmit the driving force of the driving motor or internal combustion engine to the driving wheels when an internal combustion engine or an electrical motor is provided as the drive source.
However, in a vehicle installed with only a driving motor with no internal combustion engine as the drive source, such as for example, in an electrically-powered vehicle such as a fuel cell vehicle or an electric vehicle installed with fuel cells or storage device used as the power source of the driving motor, the selection of reverse (R) position can be permitted as a transmission operation by the driver during forward running, and the running state of the vehicle can be set so as to move smoothly and continuously from the forwarding state to the reversing state through the stop state by the regenerative operation of the driving motor in the normal rotation state as running control to suit the will of the driver.
In vehicles where the running state can be changed over from the forwarding state to the reversing state smoothly by the regenerative operation of the driving motor in this way, for example, when traction control is executed to increase the gripping force of the driving wheels by controlling the regenerative torque by the regenerative operation of the driving motor according to the spinning of the driving wheels when the vehicle starts, and for example, if the condition of the driving wheels suddenly changes to the gripping condition to suit the conditions of the road surface, such as the friction coefficient and the unevenness of the road surface, the stop of the regenerative operation of the driving motor may be delayed to ensure the gripping condition, and the regenerative operation of the driving motor may continue even when the vehicle speed and the wheel speed are almost zero. In this case, the driving motor performs regenerative operation in the stop state of the vehicle, which may lead to a problem in that the vehicle starts reversing against the will of the driver who is trying to start the vehicle in the forward direction.